LCD backlight duration proportional to amount of information on the LCD display screen

ABSTRACT

A method, and device incorporating the method, permits adjustment of the on time of a light source that illuminates a display within a handheld wireless communications device. The on time may be adjusted by the amount of information to be displayed, the font size of the information, the behavioral characteristics of the end user, the type of viewing activity, and the like. An optional dim mode permits the end user to be made aware that the light illuminating the display is about to be shut off.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. patent application Ser. No. 10/788,599filed on Feb. 27, 2004, which issued as U.S. Pat. No. 7,221,964.

FIELD OF THE INVENTION

The present invention relates to the field of wireless communicationsdevices and, especially, to wireless communications devices having anelectronic display of information.

BACKGROUND OF THE INVENTION

Wireless communications device users in a business environment need tohave information comfortably and reliably. A major determiner of theeffectiveness of a wireless communications device is the weight of thebattery powering the device. Much research has occurred to try tooptimize battery performance. There are three major techniques used tooptimize battery performance: reducing the weight of the battery,increasing the energy density of the battery, and using less energy perunit time from the battery.

Lighting, data processing, alarm operation, and wireless transmissionare all power consuming activities. Current techniques use a dumb timerto determine the amount of time power is applied to the light for adisplay. These techniques have been inadequate in many cases, such aswhen there is a great amount of text to read or when the materialdisplayed requires careful reading. In these cases, the viewer needs toexercise a key board or thumb wheel to keep the light from turning offbefore the viewer is finished viewing the display screen. In othercases, where the material is quickly understood by the viewing, energyis wasted while the display remains lit beyond the point of usefulness.

Thus, there is a need for a lighting method for a display that optimizesthe use of power and optimizes the understanding of the displayedinformation by a user of the wireless communications device.

SUMMARY OF THE INVENTION

The present invention relates to a method and device that optimizes theamount of time a display is lit.

In the present invention, the device firmware determines the amount ofinformation on the display screen and then sets the light inactivitytimer to be proportional to the amount of determined information. One ormore factors are taken into consideration by a processing algorithm inthe wireless communications device. Chief amongst the factors is theamount of information displayed within the view screen. The duration ofpower being applied to the light for the display may be establishedthrough the amount of information to be displayed. Other factors thatmay be used to establish the time of duration are the font size of thecharacters to be displayed, the type of activity, and the amount ofambient light. Examples of types of activity include e-mail composition,browser use, calendar use, phone usage, e-mail reading, task lists, ande-mail message searches.

Additional aspects and features of the invention will be apparent tothose skilled in the art and include a computer program product having acomputer readable medium tangibly embodying computer executable code forcomposing a destination for an outgoing communication generated by awireless communications device for use in a wireless network.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of present invention will now be described by way of examplewith reference to attached figures, wherein:

FIG. 1 is a block diagram that illustrates pertinent components of awireless communications device that communicates within a wirelesscommunication network according to the present invention;

FIG. 2 is a more detailed diagram of a preferred wireless communicationsdevice of FIG. 1 according to the present invention;

FIG. 3 illustrates an embodiment of a backlit liquid crystal display;

FIG. 4 illustrates a first embodiment of the method of the presentinvention;

FIG. 5 illustrates a second embodiment of the method of the presentinvention;

FIG. 6 illustrates an embodiment of a light source timer-setting menu;

FIG. 7 illustrates a submenu of the menu of FIG. 6 for setting the timeout value;

FIG. 8 illustrates a submenu of the menu of FIG. 6 for setting a dimmode;

FIG. 9 illustrates an embodiment of a user profile; and

FIG. 10 illustrates an embodiment of the general method of the presentinvention.

DETAILED DESCRIPTION

The present invention relates to a method, and wireless communicationsdevice that incorporates this method, for optimizing the time a displayis in a lit state. The present invention offers a light power techniquethat is adaptive to a setting. Generally, in the present invention, thegreater the amount of information on a display, the longer the time thedisplay screen of the wireless communications device will be lit topermit a user to read a screen of information. Also, in the presentinvention, display lighting times will be increased when smaller fontcharacters are to be displayed if the amount of information increases.In an embodiment of the present invention, a lighting timing learningmode may be implemented to accommodate users with varying readingcapabilities.

A user interface for wireless communications device includes a componentto compose a destination for an outgoing communication generated by thedevice. The component provides alternative composition means comprisinga prompt for receiving the destination from a user; and a hot list ofcandidate destinations from which the user may select the destination.The component may be invoked directly from a home screen of the userinterface by keying the destination. Entry from the main screen maypopulate the prompt with the keyed destination to speed callingoperations.

FIG. 1 is a block diagram of a communication system 100 that includes amobile station 102 that communicates through a wireless communicationnetwork symbolized by station 104. Mobile station 102 preferablyincludes a visual display 112, a keyboard 114, and perhaps one or moreauxiliary user interfaces (UI) 116, each of which is coupled to acontroller 106. Controller 106 is also coupled to radio frequency (RF)transceiver circuitry 108 and an antenna 110.

Typically, controller 106 is embodied as a central processing unit (CPU)that runs operating system software in a memory component (not shown).Controller 106 will normally control overall operation of mobile station102, whereas signal-processing operations associated with communicationfunctions are typically performed in RF transceiver circuitry 108.Controller 106 interfaces with device display 112 to display receivedinformation, stored information, user inputs, and the like. Keyboard114, which may be a telephone type keypad or full alphanumeric keyboard,is normally provided for entering data for storage in mobile station102, information for transmission to network 104, a telephone number toplace a telephone call, commands to be executed on mobile station 102,and possibly other or different user inputs.

Mobile station 102 sends communication signals to and receivescommunication signals from the wireless network 104 over a wireless linkvia antenna 110. RF transceiver circuitry 108 performs functions similarto those of a base station and a base station controller (BSC) (notshown), including for example modulation/demodulation and possiblyencoding/decoding and encryption/decryption. It is also contemplatedthat RE transceiver circuitry 108 may perform certain functions inaddition to those performed by a BSC. It will be apparent to thoseskilled in art that RF transceiver circuitry 108 will be adapted toparticular wireless network or networks in which mobile station 102 isintended to operate.

Mobile station 102 includes a battery interface (IF) 134 for receivingone or more rechargeable batteries 132. Battery 132 provides electricalpower to electrical circuitry in mobile station 102, and battery IF 132provides for a mechanical and electrical connection for battery 132.Battery IF 132 is coupled to a regulator 136 that regulates power to thedevice. When mobile station 102 is fully operational, an RF transmitterof RF transceiver circuitry 108 is typically keyed or turned on onlywhen it is sending to network, and is otherwise turned off to conserveresources. Similarly, an RF receiver of RF transceiver circuitry 108 istypically periodically turned off to conserve power until it is neededto receive signals or information (if at all) during designated timeperiods.

Mobile station 102 operates using a Subscriber Identity Module (SIM) 140which is connected to or inserted in mobile station 102 at a SIMinterface (IF) 142. SIM 140 is one type of a conventional “smart card”used to identify an end user (or subscriber) of mobile station 102 andto personalize the device, aong other things. Without SIM 140, themobile station terminal is not fully operational for communicationthrough the wireless network. By inserting SIM 140 into mobile station102, an end user can have access to any and all of his/her subscribedservices. SIM 140 generally includes a processor and memory for storinginformation. Since SIM 140 is coupled to SIM IF 142, it is coupled tocontroller 106 through communication lines 144. In order to identify thesubscriber, SIM 140 contains some user parameters such as anInternational Mobile Subscriber Identity (IMSI). An advantage of usingSIM 140 is that end users are not necessarily bound by any singlephysical mobile station. SIM 140 may store additional user informationfor the mobile station as well, including date book (or calendar)information and recent call information.

Mobile station 102 may consist of a single unit, such as a datacommunication device, a multiple-function communication device with dataand voice communication capabilities, a personal digital assistant (PDA)enabled for wireless communication, or a computer incorporating aninternal modem. Alternatively, mobile station 102 may be amultiple-module unit comprising a plurality of separate components,including but in no way limited to a computer or other device connectedto a wireless modem. In particular, for example, in the mobile stationblock diagram of FIG. 1, RF transceiver circuitry 108 and antenna 110may be implemented as a radio modem unit that may be inserted into aport on a laptop computer. In this case, the laptop computer wouldinclude display 112, keyboard 114, one or more auxiliary Uls 116, andcontroller 106 embodied as the computer's CPU. It is also contemplatedthat a computer or other equipment not normally capable of wirelesscommunication may be adapted to connect to and effectively assumecontrol of RF transceiver circuitry 108 and antenna 110 of a single-unitdevice such as one of those described above. Such a mobile station 102may have a more particular implementation as described later in relationto mobile station 202 of FIG. 2.

FIG. 2 is a detailed block diagram of a preferred mobile station 202.Mobile station 202 is preferably a two-way wireless communication devicehaving at least voice and advanced data communication capabilities,including the capability to communicate with other computer systems.Depending on the functionality provided by mobile station 202, it may bereferred to as a data messaging device, a two-way pager, a cellulartelephone with data messaging capabilities, a wireless Internetappliance, or a data communication device (with or without telephonycapabilities). Mobile station 202 may communicate with any one of aplurality of fixed transceiver stations 200 within its geographiccoverage area.

Mobile station 202 will normally incorporate a communication subsystem211, which includes a receiver, a transmitter, and associatedcomponents, such as one or more (preferably embedded or internal)antenna elements and, local oscillators (LOs), and a processing modulesuch as a digital signal processor (DSP) (all not shown). Communicationsubsystem 211 is analogous to RF transceiver circuitry 108 and antenna110 shown in FIG. 1. As will be apparent to those skilled in field ofcommunications, particular design of communication subsystem 211 dependson the communication network in which mobile station 202 is intended tooperate.

Network access is associated with a subscriber or user of mobile station202 and therefore mobile station 202 requires a Subscriber IdentityModule or “SIM” card 262 to be inserted in a SIM IF 264 in order tooperate in the network. SIM 262 includes those features described inrelation to FIG. 1. Mobile station 202 is a battery-powered device so italso includes a battery IF 254 for receiving one or more rechargeablebatteries 256. Such a battery 256 provides electrical power to most ifnot all electrical circuitry in mobile station 202, and battery IF 254provides for a mechanical and electrical connection for it. The batteryIF 254 is coupled to a regulator (not shown) that provides power V+ toall of the circuitry.

Mobile station 202 includes a microprocessor 238 (which is oneimplementation of controller 106 of FIG. 1) that controls overalloperation of mobile station 202. Communication functions, including atleast data and voice communications, are performed through communicationsubsystem 211. Microprocessor 238 also interacts with additional devicesubsystems such as a display 222, a flash memory 224, a random accessmemory (RAM) 226, auxiliary input/output (I/O) subsystems 228, a serialport 230, a keyboard 232, a speaker 234, a microphone 236, a short-rangecommunications subsystem 240, and any other device subsystems generallydesignated at 242. Some of the subsystems shown in FIG. 2 performcommunication-related functions, whereas other subsystems may provide“resident” or on-device functions. Notably, some subsystems, such askeyboard 232 and display 222, for example, may be used for bothcommunication-related functions, such as entering a text message fortransmission over a communication network, and device-resident functionssuch as a calculator or task list. Operating system software used bymicroprocessor 238 is preferably stored in a persistent store such asflash memory 224, which may alternatively be a read-only memory (ROM) orsimilar storage element (not shown). Those skilled in the art willappreciate that the operating system., specific device applications, orparts thereof may be temporarily loaded into a volatile store such asRAM 226.

Microprocessor 238, in addition to its operating system functions,preferably enables execution of software applications on mobile station202. A predetermined set of applications that control basic deviceoperations, including at least data and voice communicationapplications, will normally be installed on mobile station 202 duringits manufacture. A preferred application that may be loaded onto mobilestation 202 may be a personal information manager (PIM) applicationhaving the ability to organize and manage data items relating to theuser such as, but not limited to, instant messaging (IM), e-mail,calendar events, voice mails, appointments, and task items. Naturally,one or more memory stores are available on mobile station 202 and SIM256 to facilitate storage of PIM data items and other information.

The PIM application preferably has the ability to send and receive dataitems via the wireless network. In a preferred embodiment, PIM dataitems are seamlessly integrated, synchronized, and updated via thewireless network, with the mobile station user's corresponding dataitems stored and/or associated with a host computer system therebycreating a mirrored host computer on mobile station 202 with respect tosuch items. This is especially advantageous where the host computersystem is the mobile station user's office computer system. Additionalapplications may also be loaded onto mobile station 202 through network200, an auxiliary I/O subsystem 228, serial port 230, short-rangecommunications subsystem 240, or any other suitable subsystem 242, andinstalled by a user in RAM 226 or preferably a non-volatile store (notshown) for execution by microprocessor 238. Such flexibility inapplication installation increases the functionality of mobile station202 and may provide enhanced on-device functions, communication-relatedfunctions, or both. For example, secure communication applications mayenable electronic commerce functions and other such financialtransactions to be performed using mobile station 202.

In a data communication mode, a received signal such as a text message,an e-mail message, or web page download will be processed bycommunication subsystem 211 and input to microprocessor 238.Microprocessor 238 will preferably further process the signal for outputto display 222, to auxiliary I/O device 228 or both as described furtherherein below with reference to FIGS. 3-7. A user of mobile station 202may also compose data items, such as e-mail messages, for example, usingkeyboard 232 in conjunction with display 222 and possibly auxiliary I/Odevice 228. Keyboard 232 is preferably a complete alphanumeric keyboardand/or telephone-type keypad. These composed items may be transmittedover a communication network through communication subsystem 211.

For voice communications, the overall operation of mobile station 202 issubstantially similar, except that the received signals would be outputto speaker 234 and signals for transmission would be generated bymicrophone 236. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on mobilestation 202. Although voice or audio signal output is preferablyaccomplished primarily through speaker 234, display 222 may also be usedto provide an indication of the identity of a calling party, duration ofa voice call, or other voice call related information, as some examples.

Serial port 230 in FIG. 2 is normally implemented in a personal digitalassistant (PDA)-type communication device for which synchronization witha user's desktop computer is a desirable, albeit optional, component.Serial port 230 enables a user to set preferences through an externaldevice or software application and extends the capabilities of mobilestation 202 by providing for information or software downloads to mobilestation 202 other than through a wireless communication network. Thealternate download path may, for example, be used to load an encryptionkey onto mobile station 202 through a direct and thus reliable andtrusted connection to thereby provide secure device communication.

Short-range communications subsystem 240 of FIG. 2 is an additionaloptional component that provides for communication between mobilestation 202 and different systems or devices, which need not necessarilybe similar devices. For example, subsystem 240 may include an infrareddevice and associated circuits and components, or a Bluetooth™communication module to provide for communication with similarly-enabledsystems and devices. Bluetooth™ is a registered trademark of BluetoothSIG, Inc.

In accordance with an embodiment of the invention, mobile station 202 isa multi-tasking wireless communications device configured for sendingand receiving data items and for making and receiving voice calls. Toprovide a user-friendly environment to control the operation of mobilestation 202, an operating system resident on station 202 (not shown)provides a GUI having a main screen and a plurality of sub-screensnavigable from the main screen. The tasks performed by the multi-taskingwireless communications device may include e mail composition, e mailmessage display, web based browsing, calendar, phone list, and e mailmessage search.

In the preferred embodiment, the display on the wireless communicationsdevice is a liquid crystal display (LCD), as illustrated in FIG. 3. In ageneral construction, the LCD is composed of three layers: a topsubstrate, a liquid crystal layer, and a bottom substrate, A liquidcrystal display may operate in a light reflective mode when ambientlight is sufficient or may be lit by a light source within or oil thewireless communications device. When the LCD is illuminated by a lightsource 308 in a back lighting mode, the top and bottom substrates 302,306 must be sufficiently transparent to provide a viewable display. Atleast one of the substrates may be an active matrix substrate with thinfilm transistors. Alternatively, the LCD may be a passive matrix device.Included as part of one or both of the substrates may be one or morebrightness enhancing, light scattering, colour filter, black matrix,retarder, and/or adhesive layers. The liquid crystal layer 304 may betwisted nematic, super twisted nematic, cholesteric, discoidal, nematic,or the like. Where feasible, two or more liquid crystals may be usedtogether as a mixture or in adjacent regions of the liquid crystaldisplay. The light source 308 is preferably a light emitting diode (LED)for reasons of cost, compactness, luminance, and weight. The LED ispreferably placed behind the liquid crystal display in relation to aviewer, but may be placed, additionally or optionally, at the edge or onthe viewer's side of the liquid crystal display. To maximize the amountof light utilized, a reflector 310 is preferably is disposed beneath thelight source 308.

As the light source 308 for the display consumes power as a function ofbeing turned on and intensity when turned on, it is important tooptimize the on time and, optionally, intensity. This is accomplished byrelating turn on time (and, optionally, intensity) to one or morefactors. Factors used in determining the on time for the light sourcemay include the amount of information to be displayed, font size of thecharacters to be displayed, the type of task being performed, andambient light levels. Ambient light levels may be sensed by a lightsensor and may be used to determine a particular intensity of lightingand/or a particular duration of the lighting. This sensor, ifimplemented, is preferably placed at the edge of the LCD to minimize auser's risk of covering up the sensor and to more accurately sense thelight level received by the LCD. FIG. 10 illustrates an embodiment of amethod of the present invention in which the light is turned on 902. Ifno light has been turned on, other processing continues 904 When thelight is turned on, as by the user hitting the backlight key or fromhitting any key in an automatic mode, multiple factors selected by amanufacturer or end user 906 may be incorporated into an algorithm ormay be simply multiplied together with a default time to establish atime on value to be loaded into a timer register 908. The time on valueis loaded into the timer 910 for a count down operation or is used in acomparator operation for a count up operation 912. The timer countup/down continues 914 until the timer times out 912 unless the userscrolls a thumbwheel or pushes a key 922 causing the timer to reload thetime on value. An optional dim mode may be implemented 916 such thatwhen a light on timer time out occurs, the end user is not left in thedark but has some warning that the light will be extinguish within ashort period of time 918. That is, the dim mode may cause the light todim for a preselected time before shutting the light off completely. Thedim mode time may be selectable by the manufacturer or end user or both.

FIGS. 4 and 5 illustrate more specific embodiments of the method of thepresent invention. In FIG. 4, activity typing 402 and amount ofinformation to be displayed 404 determine a timer quantity. A defaulttime value may also be used to determine the timer quantity. Forexample, if the activity typing factor were 2, the amount of informationwere 5, and the default time value were 10 seconds, the resulting timeon product would be 100 seconds. The wireless communications device mayhave a learning mode in which behavioural heuristics of the end user maybe kept as to how often a user forces the backlight on or off todetermine if time outs need to be lengthened or shortened. In FIG. 4, ifa behavioural factor were present or selected 406, the behaviouralfactor may be multiplied with the timer quantity to determine a newtimer quantity. In the embodiment of the method illustrated by FIG. 5,the type of activity 502, the amount of information (or, content) 504,and the font size (or type) 506 are used to derive the time on of thelight source 508 The amount of information may be determined through thenumber of ASCII characters to be displayed on the screen, the number ofinformative ASCII characters to be displayed on the display screen(e.g., characters that are not the space character), the number of datawords retrieved from memory for the display, the number of data wordsbuffered representing characters contemporaneously displayed asdetermined by the selected font size, and the like,

FIGS. 6-8 illustrate an embodiment of the method of the presentinvention in which menus are used to set the light source time on valuewith an optional dim mode. In FIG. 6, the end user or manufacturer maychoose to set the time on factors and/or the dim mode duration time froma lighting options menu. In FIG. 7, when the time on factors menu isselected, the end user or manufacturer may choose to set the light ontiming to the amount of data to be displayed, font size (or type),behavioural heuristics, activity, and the like. The behaviouralheuristics may include the keeping of a log file of backlight usageduration for an activity in which the backlight usage duration isaveraged and/or is weighted more heavily for recent activity of a user.The log file of backlight usage duration may also be set to cutoffconsideration of any usage before a predetermined date such as anyactivity more than a month old. In FIG. 8, a dim mode duration time menupermits the dim mode to be used as a warning to the end user that thelighting is to be timed out. If the dim mode warning is selected, thedim mode warning time out may be set. This could be a value of only onesecond or two or may be a higher value, such as 30 seconds or oneminute.

In an embodiment of the present invention, as illustrated in FIG. 9, auser profile may be established. The user profile, unique to each userif there are more than one users, may provide a unique default time forillumination duration for an activity, such e mail, calendar, and themain screen. A reset to default may be provided as an option in case fora new user or a user who wishes to have his or her use activityrecalibrated.

The present invention may be practiced in a variety of ways. The on timemay also be made determinable by the type of information on the display,e.g., graphs or photographs. Since some activities, such as e mailcomposition and message reading, are more likely to benefit than otheractivities for light source on time adjustability, the invention may bepracticed such that only certain activities entered by an end userresult in adjustment to the on time for the light source while othersrequire no special adjustment. Although a dim power mode has beendescribed, other power modes may be implemented instead or in addition,such as an idle mode, a screen saver mode, a standby mode, and a powerdown mode. The light source illuminating the LCD may use discretelevels, as described above, or may have continuously variable lightintensity. A dedicated button may be provided on the body of thewireless communications device to permit a user to step through variousstates, such as high to dim to off to high.

The above-described embodiments of the present application are intendedto be examples only. Those of skill in the art may effect alterations,modifications and variations to the particular embodiments withoutdeparting from the scope of the application. The invention describedherein in the recited claims intends to cover and embrace all suitablechanges in technology.

1. A computer-implemented method for controlling illumination of adisplay screen on a mobile device, comprising: turning on a light sourceto illuminate the display screen; identifying a font size of informationdisplayed on the display screen; determining an amount of time to keepthe light source turned on based only on the identified font size and adefault time value, the amount of time being inversely proportional tothe font size; and keeping the light source turned on at a firstintensity level for the amount of time, and then turning the lightsource to a second intensity level.
 2. The method of claim 1, whereinthe second intensity level is an off state of the light source.
 3. Themethod of claim 1, wherein the second intensity level is a dim mode ofthe light source.
 4. A computer-implemented method for controllingillumination of a display screen on a mobile device, comprising: turningon a light source to illuminate the display screen; identifying a typeof task being performed by the mobile device to display information onthe display screen; determining an amount of time to keep the lightsource turned on based only on the identified type of task; and keepingthe light source turned on at a first intensity level for the amount oftime, and then turning the light source to a second intensity level. 5.The method of claim 4, wherein the second intensity level is an offstate of the light source.
 6. The method of claim 4, wherein the secondintensity level is a dim mode of the light source.
 7. Acomputer-implemented method for controlling illumination of a displayscreen on a mobile device, comprising: turning on a light source toilluminate the display screen; identifying a stored behavioral patternfor an individual user of the mobile device that indicates an averagetime that the user requires the display screen to be illuminated;determining an amount of time to keep the light source turned on basedat least in part on the stored behavioral pattern; and keeping the lightsource turned on at a first intensity level for the amount of time, andthen turning the light source to a second intensity level.
 8. The methodof claim 7, wherein the second intensity level is an off state of thelight source.
 9. The method of claim 7, wherein the second intensitylevel is a dim mode of the light source.
 10. The method of claim 7,wherein the average time is weighted more heavily for more recent usageby the user.
 11. The method of claim 7, wherein the average time isbased on a log file of backlight usage duration.
 12. The method of claim7, wherein the average time is calculated by the mobile device.